1. Field of the Invention
This invention relates to a combustion device for an engine, and particularly to an auxiliary assembly for improving the combustion efficiency of an engine while running so as to provide a suitable amount of fresh air to dilute an over-rich mixture,
2. Description of the Prior Art
When a conventional engine is running, an amount of air will run in the crankcase of the engine so as to scavenge the moisture and fuel gas in the crankcase under cold condition. The scavenging function has to be done by means of a system; otherwise, the crankcase will be accumulated with water and acid matter to choke the lubricant pipe, and to cause metal corrosion. The moisture and fuel gas should not be exhausted in the air directly because of air pollution. The crankcase is usually provided with a closed ventilation system, The air passing through the air cleaner is taken into the crankcase so as to scavenge the moisture and fuel gas through a conduit, the intake manifold, and into the cylinder before being burned.
During an engine idling, there is more air to be sucked into the intake manifold through the crankcase, i.e., the gas mixture will be diluted to cause abnormal running; in order to prevent such condition, the outlet of the crankcase has a crankcase ventilation valve to adjust the air volume.
In the prior art, a fuel-saving unit for the internal combustion engine, such as disclosed in Taiwan Patent NO. 80201784, is substantially a rotary unit mounted between the carburetor and the intake manifold. The rotary unit is a cylindrical part fixedly mounted on the intake pipe wall of the intake manifold; the upper part of the rotary unit has a hole for mounting a rotary blade assembly, a bush and a screw. Each blade is furnished with a plurality of oblique grooves. Before entering the intake manifold, the gas mixture is further atomized with the rotary unit so as to be burned completely in the combustion chamber for the purpose of saving fuel. Since such a unit is mounted between the carburetor and the intake manifold, some parts must be removed before installing the unit in place, aside from drilling hole on the intake manifold wall; in case of improper mounting, other parts will be damaged.
In U.S. Pat. No. 4,112,892, the fuel-saving unit is a whirling auxiliary unit mounted between the intake manifold and the crankcase ventilation pipe, but near the intake manifold, The auxiliary unit has an adjusting screw to adjust the air flow entering a whirlpool chamber; before the external air enters the intake manifold, the air will generate a whirlpool by means of a vacuum force provided with the intake manifold so as to have the external air completely mixed with the moisture and fuel gas left in the crankcase in order to obtain a complete combustion. In this invention, the screw is the only part to be used for adjusting the sectional area of the intake passage, i.e., merely further mixing the fuel gas scavenged from the crankcase ventilation system; when the vacuum force of the intake manifold is strong, the volume of the external air cannot be regulated automatically. If it is not adjusted properly, a high combustion rate under idle running will be caused.
In a prior art of Taiwan Patent NO. 79212774, the fuel-saving unit is an intake pipe mounted between the intake manifold and the carburetor; the intake pipe is loaded with a check valve and an air cleaner. An on-off valve is mounted between the check valve and the air cleaner. The check valve is to be opened and closed by means of a pressure of the engine upon running for regulating the flow of fresh air. Such a unit can have the fresh air flowing into the manifold to increase the mixing of the air and the gasoline; however, it is doubtful whether it can overcome the technical drawback of instant rich mixture or not upon an engine being accelerated and upon the throttle valve being opened widely. The specification of that invention never shows that point.